Contemporary technology may provide solutions for several applications requiring frequent and timely detection and monitoring of conditions of a biological organism or a person using analysis of metabolic products transmitted into the surrounding environment through boundaries including epithelium, epidermis, and/or mucosal membranes. Of this, methods and apparata arranged to detect components of excretory fluids (e.g. liquids pertinent to perspiration or diaphoresis or vapors pertinent to transpiration embodiments directed toward monitoring of alcohols may be of particular interest because of its relative predominance in law enforcement practices. For example, transdermal alcohol monitoring using an ankle bracelet may be an accepted solution for repeat “Driving Under the Influence” (DUI) offenders. Such a device is known to be embraced by a plurality of jurisdictions in the US and UK. Current class of transdermal bracelets have been introduced in early 2000s, and since then there has been steadily increasing deployments each year.
The devices and methods in accordance to the current invention may be related to devices optimized for detection and testing of targeted substances transmitted through at least one body boundary surface including, but not limited to, epithelium, epidermis, skin, and/or mucosal membranes. One feature contrasting the devices of the current invention from known breathalyzers may be the extent of the duration of the measuring process. Namely, the breathalyzers may be optimized for relatively infrequent short measurements under controlled or commanded conditions, while the current invention may be arranged for prolonged or frequently repeated detection and measurement during an extensive duration of time under potentially constantly variable circumstances.
In some embodiments of the current invention, an active detecting element similar to an alcohol sensor commonly used in breathalyzers may be employed. For example, such a sensor, incorporated in a bracelet, may take regular frequent reading of the vapors transpired through the body boundary of the monitored subject of interest in order to detect the presence of alcohol in the subject's body, thereby determining events of alcohol consumption. One possible challenge, in existing alcohol monitoring bracelets of the prior art, may be events of detections of false positives and negatives. Substantially all of the existing sensors detect alcohol non-exclusively, and therefore detect other reacting substances present in the surrounding environment. In addition, a number of lotions and other skin products may contain alcohol. Therefore, significant sources potentially leading to false positives may include environmental factors and/or substances unrelated to consumption of alcoholic beverages applied intentionally or unintentionally in the proximity of the monitored subject epidermis. Thus, the prior art bracelets that may incorporate a position alcohol sensor that is placed in close proximity and faces the subject's body boundary surface may be inherently suboptimal regarding false positives. They may attempt to remedy the above feature by application of complex algorithms arranged to assist in determining alcohol consumption events by monitoring and complexly processing data received from the single sensor. The above algorithms may look at the time dependence and rate of rise and fall of the alcohol readings to attempt to differentiate true alcohol consumption events. In addition, in order to decrease the percentage of false positives, the bracelet detectors of the prior art may be tuned to a less sensitive setting, therefore missing a number of low level alcohol consumption events which may be of concern for law enforcement agencies.
The apparata and methods of the current inventions may be based on application of at least two separated sensors or sensor arrays disposed at certain distance from each other and arranged to sample body-related and environment related samples generally with adjustable sensitivity levels, efficacies, and/or sampling frequencies. The analysis of such enriched set of measurement results may result in more representative alcohol consumption detections less sensitive to the false positives and negatives.
It may be noted that the apparata and the methods of the present invention may not be limited to the application involving alcohols only. Different embodiments of the current invention may be utilized in cases where other constituents of perspired or transpired fluids may be of interest. For the applications pertinent to, but not limited by, detections of lactic acid and lactates, urea, Na, Cu, Fe, Cr, Ni, Pb, 2-methilphenol (o-cresol), 4-methylphenol (p-cresol), sugars, and combinations and mixtures of the above are not exceeding the scope of the current invention. Furthermore, the detection of perspired water may be accomplished using the current invention, for example in order to monitor diaphoresis and other conditions (e.g. hyperthyroidism, hypoglycemia, menopause, diabetic ketoacidosis, renal insufficiency, pheochromolytoma, etc.) related to frequent or abnormal perspiration.
It should be noted that in some embodiments “subjects of interest” may include animals capable of transpiration or transmission of substances through pertinent body boundaries. Such embodiments may be of interest in agriculture, recreation, sports, veterinarian medical practice, and/or in practices associated with usage of animals in health-related research and testing.